No one has yet claimed responsibility for the attack at a crowded bus station Sunday, but it fits the pattern of Nigerian terrorist group Boko Haram, which began using teenage girls as suicide bombers last year.

"The girl that carried out the suicide should be around 16 years old, because her face was a bit matured," said Hassan.

At least eight of the bodies were taken to the mortuary at Damaturu Specialists Hospital, said who spoke to The Associated Press on phone. The worker insisted on anonymity because he is not authorized to speak to the press.

No one has yet claimed responsibility for the bombing but it fits the pattern of violence by Boko Haram, Nigeria's homegrown Islamic extremist group that caused an estimated 10,000 deaths last year and is fighting to impose Islamic Shariah rule over Nigeria.

Last year Boko Haram began using teenage females as suicide bombers, probably because they can evade security by hiding explosives under their hijab garments. In April the extremists kidnapped more than 200 schoolgirls who remain missing.

This is the first suicide bombing in Damaturu,, the capital of the Yobe state. The city of about 90,000 people in northeastern Nigeria has suffered several attacks by Boko Haram in past three years. On Dec. 1 Boko Haram attempted to seize Damuturu, but was repelled after a lengthy battle with many casualties.

In recent weeks Boko Haram have attacked the neighboring countries of Cameroon, Niger and Chad. Those countries and others are planning to form a joint force to help Nigeria battle the extremists.